This invention relates to the winding of coils to form a coil pack, and, more particularly, to the formation of the coil pack from a series of radially wound individual coils.
Several types of missiles are controlled through a fiber extending from the missile to its launch point. The fiber is initially wound into a pack within the missile or a canister at the launch point, and is rapidly dispensed after the missile is launched and flies toward its target. The "fiber" used in many such control systems is an electrically conducting wire such as a thin copper wire. More recently, the "fiber" has been an optical fiber that has a higher data transmission capability than does the metallic wire. The fiber is typically on the order of 0.010 inches in diameter for optical fibers and 0.005 inches in diameter for electrically conducting wires
An important element of control system is the fiber dispenser, which must receive a long length of the fiber thereon for storage. The fiber dispenser must further facilitate the payout of the fiber in an orderly manner such that the fiber does not break or sustain significant damage during dispensing. Damage to the fiber leads to a loss of communication between the launch point and the missile, and either renders the missile useless or may lead to automatic self-destruction of the missile. The fiber dispenser must achieve a smooth, damage-free payout of lengths of fiber than may range from a few kilometers for hand-fired missiles to well over a hundred kilometers for some types of ground-to-ground or air-to-ground missiles. The missile velocity may be as low as tens of kilometers per hour for torpedoes to a thousand kilometers per hour for missiles that fly through the air.
In one approach to fiber storage and payout, the fiber is wound as a series of constant-radius turns along the length of a cylindrical mandrel to form a layer, with each succeeding layer resting on the previously wound layer. During payout, each layer is successively dispensed. In this technique, the capacity of the dispenser is enlarged by increasing the number of layers. In another approach, a coil pack is built up by winding an outwardly spiralling coil onto a flange, winding a second outwardly spiralling coil axially adjacent to the first coil, and so on. During payout, each coil is successively dispensed. The capacity of the dispenser is enlarged by increasing the axial length of the coil pack by adding more coils to the end of the coil pack. Each of these geometries has its advantages for specific applications. The present invention is concerned with the second approach, wherein the coil pack is fabricated as a series of outwardly spiralling coils that are joined to each other axially.
The winding of a single outwardly spiralling coil requires careful control of the winding apparatus, and the fabrication of a coil pack with a succession of such coils presents difficult challenges both in winding the individual coils and also in positioning the coils in an efficient array. The earliest coil pack fabrication apparatus operated to wind a first spiral coil. Then a second spiral coil was wound using a series of tapered rollers in a guided, but somewhat free-form, manner axially contacting the first spiral coil, and the process was repeated. This approach is slow and is potentially inaccurate, and has a relatively high likelihood of introducing winding defects into the coil pack that can lead to fiber damage during payout. Improvements have been made, but the winding of a coil pack remains a difficult and time consuming process.
Accordingly, there is a need for an improved approach to the fabrication of coil packs. The present invention fulfills this need, and further provides related advantages.